The Environmental Microbiology of Chlorinated Aromatic Decomposition

Abstract The difficulty in predicting the microbial degradation rates of such xenobiotic chemicals as chlorinated aromatic hydrocarbons necessitates that empirical data on decomposition be collected to model the environmental fate and transport of these recalcitrant compounds. A partial list of microorganisms reported to degrade chlorinated aromatic hydrocarbons is provided. The processes of degradation, including dehalogenation, cometabolism, and synergistic mineralization, are discussed as they pertain to these halogenated compounds. Adaptation through genetic exchange within a microbial community is addressed through a brief review of the physical‐chemical factors required for plasmid transfer in the laboratory. The ecological significance of gene recruitment in response to xenobiotic stress is also considered. Because chlorinated aromatic hydrocarbons were rare in the environment until a few decades ago, they provide a unique opportunity to study the evolution of multistep catabolic pathways for the degradation of compounds with novel chemical structures.